Note: Descriptions are shown in the official language in which they were submitted.
2~036Z4
FORMED WrRE SPRING ELEMENT FOR BOX SPRING ASSEMBLIES
~ACKGR~UND AND SUMMARY OF THE INVENTIoN
This invention relates generally to mattress foundation
structures and more particularly to a box spring assembly of the type which
util~7es non-coil springs. Box spring assemblies of this general type have
been known since 1964, the first such spr mg assembly being disclosed in U.
S. Patent No. 3,286,281. S~ Lly issued patents disclosing the same
general type of ~ox spring assembly are: U. S. P~Len s Nos. 3,487,480,
3,506,987; 3,574,240; 3,574,241; 3,665,529J 3,680,157~ 3,755,833t
3,824,639; 3,852,8385 4,060,862; 4,120,058s 4,131,961t 4,195,376;
4,218,790; 4,238,861; 4,251,892~ 4,253,208; 4,339,834; 4,470,584; 4,739,977
and 4,779,293.
Box spr mg assemblies of the general type shown in the above list
of patents, all of which are owned by the assignee of this application, are
advantageous with L~ecL to the conv~ional ~ox spring assemblie~ using
coil springs h~C~llse they provide a desired stiffer foundation for the
la~LLess and cQ~ n a reduced amount of wire. m ese box spring assemblies
are also advan~ay~ous from the s~ oint of prolonged service life, ease
of assembly, and cost of m~ f~ture.
Additional box spring assemblies of this general type are shown
in U. S. Patent Nos. 3,546,7235 3,596,2995 3,722,013; 3,825,960s 3,833,9485
3,835,485; 3,869,740~ 3,990,1217 and 4,000,531.
The principal object of this invention is bo provide a spring for
a box spring assem~bly which has improved limited dbflection ch2~a~e~istics
to avoid overstressing of the spring during loading in oombination with an
upright column support which maximizes lateral stability at full
20()36Z4
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deflection. The lateral stability of the limited deflection spring helps
to insure that the spring will move in a substantially straight down~ard
direction during deflection, thereby m~n1m~7~ sk~ess that can result in
~ nPl~l deformation of the spring from lmh~lAnce~ shock loading. In
addition, the upright columns in the spring are configured so that they
diverge and the angles of divergence can be varied between individual
spring elements to optimize the lateral stability and floatation ~L~eL~ies
of the platform surface of the box spring assembly while providing very
strong resistance to relatively straight down impact loading.
Each of the springs according to the present invention has a
unitary wire body having a foot portion, an upright yieldable portion
~x~P~;n~ upward from the foot portion and a load bearing portion at the
upper end of the upright portion. The load bearing portion is a generally
horizontal deck at~Achi~g portion of the wire body which is clipped,
interlocked or otherwise attached to a generally hor;zontAl wire mattress
support deck which is in turn spaced vertically above a generally
horizontal frame. m e foot portion of the limited deflection spring
according to the present invention is attached to the generally horizontal
frame.
The upright portion of the limited deflection spring includes a
pair of horizontally spaced upright columns which diverge relative to each
other and are sll~pPn~d between the foot portion and the loading bearing
portion by separate vertically yieldable portions. Each vertically
yieldable portion is a torsion bar system which includes a pair of
generally hor~7~ntAl upper and lower torsion h~rs c~lme~ed together by a
oommon oe ntral cv~ ing bar.
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In one erho~;~Pnt of the limited deflection spring according to
the present invention, the divergent upright columns diverge upwardly so as
to position the lower ends of the upright columns relatively close together
beneath the load bearing portion. This a L~~ 1 m~ves the upright
columns tow æ d a generally vertical orientation at full deflection thus
allowing the deck at~ach~ng portion or load bearing portion to be able to
tilt, thus giving a floatation ~4v~e~y to the mattress su~rL deck.
Another emkodLment of the present invention includes downwardly
diverging upright columns which, at full deflection, provide a wide base
~lc~ezoidal support to the load bearing portion. In this a~ cJ~ L~ the
angle between the upright columns increases as the spring is moved from the
unloaded to the fully deflected position. This system forms a trapezoid
having a wider stance at the base at full deflection which m~x;mlzes
lateral st~bility. The lateral st~hility increases as the spring is
actuated. This arra~ also helps to guide the spring in a more
straight vertical deflection, thus minimizing skewness that can result in
p~r~ nt deformation of the spring from 1mh~l~n~e~d shock loading.
In contrast, in the first embo~ t above described, having
upwardly div~ L upright columns, the angle between the upright columns
tends to decrease as the spring is ~"~essed between the unloaded and the
fully deflected positions and forms a narrow base at full deflection. This
allows the load bearing portion to tilt under asymmetric loading e~ancing
the floatation ~lo~Ly.
In both embo~ nts of the present invention, the upright columns
are susp~nd~ hetw~cn the mattress support deck and the frame by separate
torsion bar systems connecting the upright columns to the load bearing
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portion and to the foot portion, respectively. m is arranye~ L provides
an improved impact resistance.
me spring elements may also be mixed within an individual box
spring assembly aL~ e~Pn~in~ upon the relative importance of
lateral stability or floatation properties which are desired with some
~ Less designs. For example, springs of the first embcdiment with
upwardly divergent columns may be positioned in the interior of the
mattress ~u~uL~ deck to enhanoe the floatation cha~ac~istics while
springs of the second emho~;~Pnt with downwardly divergent columns are
arranged around the perimeter to provide i~ v~d shock 10A~;ng and lateral
stability along the sides of the .,~Less support deck. Thus, a
combinatiQn of the spring elements may be ut;]~7e~ to achieve an overall
response that is part;~l~rly desirable in a foundation support system.
Additional hpn~f;ts and advantages of the present invention wiIl
become apparent to those skilled in the art to which this inventlon relates
from the following descripticn of the ~efe~red em~o~;mPnts and the
ApFPn~e~ claims, taken in conjunction with the ac~ u~ying drawings:
BRIEF DESCRIPTIoN OF THE DRAWINGS
Figure 1 is a rLd ~ntary perspective view of a portion of a box
spring assembly i~ o~a~ing the springs of this invention;
Figure 2 i8 a side elevational view of one emhc~;~Pnt of the
spring aocording to the present invention showing the spring undeflected in
solid lines and deflected downwardly to a limlt position in broken lines;
and
Figure 3 is another side elevational view of a second Pm~ mPnt
of the spring acoording to the present invention showing the spring
undeflected in solid lines and deflected dowllw~dly to a limit position in
broken lines. 2 o o 3 6 2 4
DETAILED DESCRIPTION OF THE INVENTION
A box spring assembly in accordance with this invention is shown in
Figure 1 and is generally design~tP~d by reference n.llllber 10. Box spring
assembly 10 includes a mattress support deck 12 disposed at a prede~..,.i~-Pd
distance above a generally rectangular frame 14 by a plurality of deck support
springs 16 and 18. The mattress support deck 12 consists of a plurality of
long deck wires 20 which run parallel to the longer dimension of the
rectangular box spring assembly 10, and a plurality of cross wire springs 22
which are arranged in a criss-crossed fashion perpendicular to the long wires
20. The long wires 20 and cross wire springs 22 are attached to a border
wire 24 via clips 26 which bind the long wires 20 and the cross wire springs
22 to the border wire 24 forming the wire grid or mattress support deck 12.
Each of the long wires 20 and cross wire springs 22 has spaced
notches 28 and 30, respectively, which are located at the inner sections of the
long and cross wires. These notches coact with the long wires and cross
wires at the intersections therebetween to prevent sliding movement of the
long wires and cross wire springs during load conditions. The notches 28 and
30 are locked in engagement by the interlocking of the spring elements as
described in C-~n~ n Patent No. 1,326,569 of January 5, 1994 2~ignP~I to
the 2~ignPe of the present invention.
The placement of spring elements 16 and 18 in Figure 1 are for
illustrative purposes only. A box spring assembly according to the present
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200362~
invention may utilize only spring elements 16, only spring elements 18 or any
colllbinalion of elements 16 and 18 as may be desired to achieve optimum
suspension characteristics. The arrangement of spring modules 18 along the
end of the box spring assembly 10 with spring element 16 arranged to the
interior is only one example. The particular distribution of spring elements 16
and 18 may be varied to achieve the desired overall box spring assembly
pelrol-llance.
Each of the spring elements 16 according to the present invention
includes a load foot portion 32 attached to the frame 14, an upright yieldable
portion 34, and a load bearing portion 36. The load bearing portion 36 is
interlocked with the long wires 20 and cross wire springs 22 as described in
C~n~ n Patent No. 1,326,569.
Similarly, each of the spring modules 18 includes a foot portion 38
attached to the box spring frame 14, an upright yieldable portion 40, and a
load bearing portion 42 interlocked with intersecting long wires 20 and cross
wire springs 22.
The principal difference between spring elements 16 and 18 lies in
the arrangement of upright yieldable portions 34 and 40. Each upright
yieldable portion 34 of spring element 16 comprises a pair of upright columns
44 which are suspended between loading bearing portion 36 and foot portion
32 by pair of upper and lower torsion bar systems 46 and 48, respectively.
The upper torsion bar system comprises an upper torsion bar 50
joining with one end of the load bearing portion 36 and a lower torsion bar 52
connected to the upper end of upright column 44. The torsion bars 50 and 52
are connected together by a central connecting bar 53. Torsion bars
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2003624
50 and 52 are generally hori7~n~1 with low~r torsion bar 52 being spaced
inwardly of upper torsion bar 50.
Lcwer torsion bar system 48 comprises ~ oU ~ pair of torsion
bars 54 and 56 c~ u~e~ ~oyeU~r by a central col~-ec~ing bar 58. One end
of torsion bar 54 is ~o~e~ed to the lower end of upright column 44. The
other end of torsion ~ æ 54 i8 ~ulu~ed to one end of colu~ec~ing bar 58.
The other end of ~ ecLing b æ 58 is co~.ec~ed to one end of lower torsion
bar 56. The other end of lower torsion bar 56 is, in turn, connected to
foot portion 32.
The two upper torsion bars 54 of lcwer torsion bar systems 48,
connected to the lower ends of upright columns 44 are positioned inwardly
of the lower torsion bars 52 of the upper torsion bar systems 48 so that
upright columns 44 diverge upward in the unloaded or undeflected position
as shown in Figure 3. As shown in the dashed line configuration in Figure
3, at full deflecticn, the angle between upright columns 44 changes only
slightly, so as to form a narrow base support for the load bearing portion
36. This allows the load bearing portian 36 to be tilted under asymmetric
loading thus enhancing the floatation cha~aeLd~istics of the limited
deflection spring 16.
In contrast, the limited deflection spring 18, shown in Figure 2,
provides a bLoadtL base support at full deflection as will be subse~ ly
described. As with spring element 16, the upright yieldable portion 40 of
each spring ele~-n~ 18 includes a pair of upright columns 45 spaoed
inwardly of the ends of the load bearing portion 42. Upright columns 45
are su~ye,~d between load bearing portion 42 and foot portion 38 by upp~r
and lower torsion bar systems 60, respectively.
2~)036Z4
Each upper torsion bar system 60 comprises a pair of spaced,
generally h~ri7~tAI upper and lower torsion bars 64 and 66, each having
one end oonnected Loyether by a central cu~ ing bar 68. The other end
of the upper torsion bar 64 is ~or~-e~ed to the load bearing portion 42.
The other end of the lower torsion bar 66 is in turn ool~ec~ed to the upper
end of upright column 45.
Similarly, the lower torsion bar system 62 comprises a pair of
generally horizontal upper and lower torsion bars 70 and 72 col~ec~ed
together by a central c~le~ing bar 74. The other end of upper torsion
bar 70 is c~l~ ee~ed to the lower end of upright column 45. The other end
of lower torsion bar 72 is connected to foot portion 38. Thus, each of the
upright columns 45 is su~ xded between the foot portion and the load
bearing portion 42 by torsion bar systems 60 and 62 which each absorb a
portion of the load as the spring is deflected to the fully deflected
position as shown in the dashed lines of Figure 2.
At full deflection, the upright columns 45 of spring element 18
forms a trApezoi~Al base having a wide stance as the upright columns 45
diverge downwardly. The angle between them increases as spring module 18
is compressed so as to form a wide ~u~LL base at full deflection. This
enhances the lateral stability of the spring element 18.
me spring element 18, in the fully deflected position as shown
in the dotted lines of Figure 2, presents a very stable platform base
represented by the widely angled upright columns 45. mis arrangement
~nhAnces the lateral stability of the spring element. The spring element
18 with the dbwnwardly divergent upright oolumns 44 helps to guide the
spring in a vertical deflective motion under load thus m;nimi7;ng skewness
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that could result in permanent deformation of spring element 18 from
mh~l~n~e~ shock loading.
In both elements 16 and 18, the sll~pPn~jon of the upright columns
44 and 45, between the load bearing portionæ 36 or 42 and foot portions 32
or 38 divides and distributes the applied load between the upper and lower
systems to avoid ovel~LLessing the spring.
In both emtDdiments of the spring according to the present
invention, spring elements 16 and 18 have notches 76 and 78 m1~sp~ced along
the upper torsion bars 50 and 64, respectively, which cradle cross wire
springs 22. The load bearing portions 36 and 42 pass over long wires 20
and cross wire spring 22 to thus interlock the long wires, cross wire
springs, and spring elements together with the cross wire springs 22 being
cradled in notches 74 or 76. This arranye~ lL eliminates the need for
clips to secure the load bearing portions 36 and 42 of the spring elements
16 and 18 to the mattress support deck 12.
The spring elements 16 and 18 may be mixed within an individual
box spring assembly arrangement such as that shown in Figure 1 to provide
increased lateral stability along the edge of the mattress support deck 12
and ~h~n oe the floatatian pko~e~ies on the interior portion of the box
spring assembly 10 by positio~ spring element 16 to the interior as
shown. Alternatively, a box spring assembly may be ~-s~ucted utili7ing
any combination of spring elements 16 and 18 to achieve the desired result.
The ~hnve described spring elements comprising upright columns
suspP~e~ between a load kearing and a foot portion by separate torsion bar
systems provides a limited deflection spring system which guides spring
deflection in a straight down direction, mi~ir;7e~ skewness that can result
in ~t~ u~IL deformation of the spring under unbalanced shock loading and
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permits selection for optimum lateral stability and floatation ~Lo~ ies
while providing strong resistance to straight down impact loading. While
the above constitutes the p eLerred ~ko~;~Pn~s of the ~leserl~ invention,
it will ke appreciated that the spring elements of the present invention
æ e susceptible to m~if~cation! v æ iation and change without depæ ting
from the proper scope and fair m~ning of the ~c~ ying claims.
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